This is where you download Booki.
Here are some links that you will find interesting:
Booki Development Mailing List : http://lists.flossmanuals.net/listinfo.cgi/booki-dev-flossmanuals.net/
Booki Bug (Issue) Tracker : http://booki-dev.flossmanuals.net
Git clone (booki) : git clone git://booki-dev.flossmanuals.net/git/booki.git
Booki User Guide : http://www.booki.cc/booki-user-guide/
Booki General Mailing List: http://lists.booki.cc/listinfo.cgi/booki-booki.cc